Kinetics of acoustic release of doxorubicin from stabilized and unstabilized micelles and the effect of temperature

Ultrasound is being investigated as a trigger mechanism to deliver high concentrations of chemotherapy drugs to cancerous tissues using polymeric micelles. In this paper, we examined the kinetics of acoustic release of doxorubicin using stabilized and non-stabilized micelles. Kinetic models were used to regress release and re-encapsulation time constants for three different compounds, namely non-stabilized Pluronic^® P105 micelles, P105 micelles stabilized using an interpenetrating network of N,N-diethylacrylamide and micelles formed by PEO-b-poly(NIPAAm-co-HEMA-lactate_n). Results showed that the kinetic release constant (k_r) depends on the micellar system under investigation. On the other hand, there is no statistically significant difference between re-encapsulation rate constants for stabilized and unstabilized micelles. We hypothesize that k_r depends on the degree of cross-linking or stabilization.     

Evaluating the impact of R&D tax credits on innovation: A microeconometric study on Canadian firms

This study examines the effect of R&D tax credits on innovation activities of Canadian manufacturing firms. Over the 1997-1999 period the Federal and Provincial R&D tax credit programs were used by more than one third of all manufacturing firms and by close to two thirds of firms in high-technology sectors. We investigate the average effect of R&D tax credits on a series of innovation indicators such as: number of new products, sales with new products, originality of innovation, etc. using a non-parametric matching approach. Compared to a hypothetical situation in the absence of R&D tax credits, recipients of tax credits show significantly better scores on most but not all performance indicators. We therefore conclude that tax credits lead to additional innovation output.     

Mapping stone surface temperature fluctuations: Implications for lichen distribution and biomodification on historic stone surfaces

The exposure of historic stone to processes of lichen-induced surface biomodification is determined, first and foremost, by the bioreceptivity of those surfaces to lichen colonization. As an important component of surface bioreceptivity, spatiotemporal variation in stone surface temperature plays a critical role in the spatial distribution of saxicolous lichen on historic stone structures, especially within seasonally hot environments. The ornate limestone and tufa stairwell of the Monastery of Cartuja (1516), Granada, Spain, exhibits significant aspect-related differences in lichen distribution. Lichen coverage and diurnal fluctuations in stone surface temperature on the stairwell were monitored and mapped, under anticyclonic conditions in summer and winter, using an infrared thermometer and Geographical Information Systems approach. This research suggests that it is not extreme high surface temperatures that determine the presence or absence of lichen coverage on stonework. Instead, average stone surface temperatures over the course of the year seem to play a critical role in determining whether or not surfaces are receptive to lichen colonization and subsequent biomodification. It is inferred that lichen, capable of surviving extreme surface temperatures during the Mediterranean summer in an ametabolic state, require a respite period of lower temperatures within which they can metabolize, grow and reproduce. The higher the average annual temperature a surface experiences, the shorter the respite period for any lichen potentially inhabiting that surface. A critical average temperature threshold of approximately 21 °C has been identified on the stairwell, with average stone surface temperatures greater than this generally inhibiting lichen colonization. A brief visual condition assessment between lichen-covered and lichen-free surfaces on the limestone sections of the stairwell suggests relative bioprotection induced by lichen coverage, with stonework quality and sharpness remaining more defined beneath lichen-covered surfaces. The methodology employed in this paper may have further applications in the monitoring and mapping of thermal stress fatigue on historic building materials.     

Ivan Illich's Late Critique of Deschooling Society: “I Was Largely Barking Up the Wrong Tree”

In this article, Rosa Bruno‐Jofré and Jon Igelmo Zaldívar examine Ivan Illich's own critique of Deschooling Society, and his subsequent revised critique of educational institutions and understanding of education, within the context of both his personal intellectual journey and the general epistemological shift that started to take shape in the early 1980s. Bruno‐Jofré and Zaldívar consider how, over time, Illich refocused his quest on examining the roots (origin) of modern certitudes (such as those related to education) and explored how human beings are integrated into the systems generated by those “certainties.” Illich engaged himself in historical analysis rather than providing responses to specific contemporary problems, while maintaining an interest in the relation between the present and the past. Under the metaphors of the word, the page, and the screen, he identified three great mutations in Western social imaginaries and the reconstruction of the individual self. Bruno‐Jofré and Zaldívar argue that while his written work, including Deschooling Society, generally had an apophatic character, his critique of education, particularly in the late 1980s and 1990s, is intertwined with his analysis of the parable of the Good Samaritan and his belief that modernity is an outcome of corrupted Christianity.     

Testing Extension Services through AKAP Models

Abstract

Purpose: The aim of the paper is to analyse the attitude of Italian farms in gaining access to agricultural extension services (AES).

Design/methodology/approach: The ways Italian farms use AES are described through the AKAP (Awareness, Knowledge, Adoption, Product) sequence. This article investigated the AKAP sequence by submitting a questionnaire to a sample of Italian farms, providing questions on each step of the sequence.

Findings: The results confirm the validity of the model and the necessity to evaluate AES in each phase of the sequence, through an in-depth analysis of the possible motivation for not adopting them.

Practical implications: The functional repositioning of agriculture redefines the role of the farm, by introducing new possibilities of production and by fostering multifunctional activities. In this context, new tasks for AES emerge, aiming at sustaining farm development along either sectorial or territorial paths. Difficulties in adopting AES call for both fostering higher levels of access to services on behalf of farms and the adequate supply of services to farms' new needs.

Originality/value: AKAP models have been prevailingly used in developing countries to evaluate the efficacy of extension in increasing agricultural productivity. This article demonstrates how this model could be of help in developed agriculture too in performing new lines of development rooted in the new models of multifunctional agriculture.     

Instrucción,aprendizaje e interacción profesor-alumno. Un estudio de observación en el aula

Resumen

Este trabajo aborda el estudio de la incidencia de los procesos de enseñanza en el aumento de conocimientos y destrezas de un grupo de niños paralíticos cerebrales en los primeros ciclos de enseñanza formal. Ello se hace a través de la puesta en relación de la ganancia que los sujetos manifiestan en sus rendimientos en una prueba criterial con datos de observaciones sobre las actividades realizadas en el aula. Los resultados muestran la existencia de un progreso en todas las áreas evaluadas, sin que parezca influir el nivel de afectación motora o del habla. Se observa que sólo menos de un tercio de las tareas escolares se plantean por encima del nivel de conocimientos previos del alumno, en estos casos la forma de interacción entre alumno y profesor toman características peculiares que permiten caracterizar la forma de trabajo en la zona de desarrollo próximo.     

Evaluación escolar de la escritura inicial

Resumen

Este estudio analiza la evaluación en relación con una tarea escolar específica, confrontando ta adjudicación y justificación de la valoración obtenida en situación experimental con los niveles establecidos por investigaciones anteriores sobre la psicogénesis de adquisición de la lengua escrita.

Se entrevistó a profesores de pre-escolar y ciclo inicial de EGB, solicitándose una evaluación de producciones escritas dt distintos niveles conceptuales, producidas por alumnos de último preescolar (cinco-seis años). En el trabajo se analizan diez entrevistas.

Los resultados muestran que la tarea de evaluar escrituras tempranas presenta grandes dificultades. Como prueba están la dispersión dt puntajes y falta de estabilidad de criterios usados, hechos que pueden ser atribuidos más a la inadecuación del marco teórico interpretativo usado por los evaluadores, que a dificultades imputables a las técnicas e instrumentos de evaluación.

Se apunta la necesidad de aportar a la práctica pedagógica elementos que contemplen y permitan entender los procesos constructivos implicados en las escrituras para evaluar.     

Reasons for the collaborative difficulties between psychoeducational consultants and teachers: an exploratory analysis / Análisis exploratorio de las variables relacionadas con las dificultades de los asesores psicopedagógicos para colaborar con los profesores

Abstract

This paper examines whether the difficulties in collaboration identified in the sessions of five consultants working with teachers and whether the consultants’ high participation (a type of hyper-responsibility) are related to the ongoing episode of the problem solving process, the origin of the request, and the topic of the session. Results show that collaboration difficulties tend to be more frequent when consultants and teachers discuss teaching-learning processes and that the consultants’ hyper-responsibility is more common: (a) when they are looking for solutions, (b) when they start some action with the support of the tradition of the educational setting or the support of the regulation, and (c) when they are discussing career guidance and mentoring.     

Teaching the teacher: exploring STEM graduate students’ nature of science conceptions in a teaching methods course

ABSTRACT

Graduate students regularly teach undergraduate STEM courses and can positively impact students’ understanding of science. Yet little research examines graduate students’ knowledge about nature of science (NOS) or instructional strategies for teaching graduate students about NOS. This exploratory study sought to understand how a 1-credit Teaching in Higher Education course that utilised an explicit, reflective, and mixed-context approach to NOS instruction impacted STEM graduate students’ NOS conceptions and teaching intentions. Participants included 13 graduate students. Data sources included the Views of Nature of Science (VNOS-Form C) questionnaire administered pre- and post-instruction, semi-structured interviews with a subset of participants, and a NOS-related course project. Prior to instruction participants held many alternative NOS conceptions. Post-instruction, participants’ NOS conceptions improved substantially, particularly in their understandings of theories and laws and the tentative nature of scientific knowledge. All 12 participants planning to teach NOS intended to use explicit instructional approaches. A majority of participants also integrated novel ideas to their intended NOS instruction. These results suggest that a teaching methods course for graduate students with embedded NOS instruction can address alternative NOS conceptions and facilitate intended use of effective NOS instruction. Future research understanding graduate students' NOS understandings and actual NOS instruction is warranted.